Controllably dispensing fluid into a compartment from a reservoir is a common problem. Many devices have been developed including complex valve and pump systems, float controlled systems and drip dispensing systems. A simple and effective product having no moving parts and no critical seals was needed prior to this invention.
An example of a prior art application of such a device is a self-watering planter used to provide water to a plant for an extended period of time. Many household plants require watering on a weekly or more frequent basis depending upon the type of plant, humidity, soil type and other factors. Many people fail to regularly water their plants due to inadvertence. In addition, plants that require frequent watering may be neglected during vacation periods. Self-watering planters generally suffer from certain disadvantages such as complexity of the apparatus, excessive cost, tendency to overflow, or difficulty in refilling.
An example of a prior art device for irrigating flower pots is disclosed in U.S. Pat. No. 3,753,315 to Adam. The Adam device includes a hermetically sealed reservoir which includes a cap to maintain the hermetic seal in the reservoir. The flower pot disclosed in the Adam patent allows water to fill a lower cavity until the upper edge of an air entry opening at the bottom of an air pipe is covered. Water is fed to a sponge located in a cavity at the base of the flower pot. Water flow is regulated by evaporation of water from another cavity, which allows water to flow until the air entry opening is again covered by water.
Another example of a prior art approach is disclosed in U.S. Pat. No. 4,885,870 to Fong, which discloses a plant container comprising a pot surrounded by a water reservoir. A vent pipe permits air to enter an upper portion of the hermetically sealed reservoir when the lower end of the vent is not covered by water. The opening in which water is supplied to the planter is closed by a cap to maintain the hermetic seal in the reservoir.
Another example is disclosed in U.S. Pat. No. 3,903,644 to Swift et al, which discloses a vacuum-controlled water dispensing flower pot. The Swift patent discloses a planter having holes in the base of the reservoir which allow water to flow from the air-tight reservoir into the base of the planter. When the level of water in the planter is above the holes, the vacuum in the reservoir prevents the flow of water into the plant containing chamber. Upon removal of a cap from the reservoir, loss of vacuum pressure permits flooding of the plant containing portion of the planter.
The defects and problems encountered by the above-identified patents are solved by the simple and effective apparatus proposed in the invention as summarized below.